Commutator construction.



Patented; Feb. 9, 1909.

UNITED STATES PATENT OFFICE.

HOWARD H. RALSTON, OF NORWOOD, OHIO, ASSIGNOR TO ALLIS-CHALMERS COMPANY, A CORPORATION OF NEW JERSEY, AND THE BULLOCK ELECTRIC MANUFACTURING COM* PANY, A CORPORATION OF OHIO.

COIVIMUTA'IO R CONSTRUCTION.

Specification of Letters latent.

Patented Feb. 9, 1909.

To all wlzem'ii may concern:

Be it known that I, lTlOWARD H. RALsToN, citizen ofthe United States, residing at Norwood, in the countyof Hamilton and State of Ohio, have invented certain new and useful Improvements in Commutator Construction,

of which the following is a full, clear, and eX act specification.

My invention rglates to the construction of commutators for dynamoelectric machines.

T he bars or segments of commutators are generally notched at their ends so that they can be readily clamped in place by rings which fit into said notches and draw the bars tightly together. These clampingrings, especially m the larger machines, are often made of a single casting sawed into a number of parts for convenience in assembling and shipping. When again put together the saw kerfs between the adjacent parts of the ring permit dust and small metallic particles to sift througln and finally lodge beneath the commutator .bars. In the course of time this material which has sifted in is liable to short circuit adjacent commutator bars. Considerable trouble has also been experienced in assembling and repairing commutators because of the absence of any supporting means for the conn'uutator bars when the clamping rings are not in place.

It is the object of my present invention to provide means whereby the difiiculties above set forth may be overcome.

\Vith this object in view, my invention consists in certain novel. features of construction Which will appear from "the description and drawings and will be particularly pointed out in the claims.

Figure 1 is a section through a commutator embodying my invention taken on the line 1- 1 of Fig. 2; and Fig. 2 is an end elevation partly in section on the line 2-2 of the commutator shown. in Fig. 1.

The commutator spider 11) may be made either in one or in several parts as desired.

,Clamping rings 11 and .1? are fastened to the flanges oi' the spider 10 and are so shaped that they lit into the notches of the commutai or bars or segments 13, insulating cones 1 1 being placed between said rings and said conimutator bars. (jommutator necks 15 C013:

nect the commutator bars with the armature Winding. The ring 11, at the armature end of the commutator, may be-made of one or more pieces, preferably the latter so that the commutator may readily be shipped in parts. The ring 12 at the opposite end of the commutator is preferably made of a larger number of segments. The segments of both rings are generally formed by sawing radially a complete ring.

Rings 16 and 16 fit tightly in slots in the outer periphery of spider 10. These rings are of insulating material and are hard enough to support the weight of the commutator bars while soft enough to give under the pressure with which the clamping rings are forced into place. They are each preferably made of two thicknesses of material built up in sections with the joint broken as shown/in Fig. 2, though if desired but one thickness of material may be used.

In assembling or repairing the commutator any section thereof may be brought uppermost so that the bars 13 of said section will rest upon the rings.16 and 16 The section of the clamping ring 12 corresponding to that section of the commutator may then be fastoned in place or removed, the commutator bars remaining in place by their own weight.

In clamping the bars 13 in lace the rings 16 and 16 are crushed slig ltly. If it is found necessary, the mica strips between the adjacent commutator bars may be cut away slightly just over the rings 16 and 16 so that thelatter will not force them outward. Furthermore the rings 16 and 16 prevent any dust or other material which may sift through the saw kerfs 17 between the segments of the rings 11 and 12 from getting in under the bars 13, thus lessening the danger of short-circuit. If the ring 11 is made of one piece, so that no saw kerfs therein admit foreign matter, the ring 16 may be omitted if desired, as during as sembling or repairing sufficient support for plurality of commutator segments, means ior clamping said segments in position relative to said spider, and a ring of insulating material in the space between said spider and said segments but occupying less than all of said space.

2. In a commutator for dynamo-electric machines, the combination of a spider, a plurality of commutator segments, a ring for clamping said segments in position relative to said spider, said ring consisting of a plurality of parts, and a comparatively narrow ring of insulating material between said commutating segments and said spider and adjacent to said clamping ring.

3. In a commutator, the combination of a plurality of commutator segments, a sup porting spider therefor, twoclamping rings for clamping said segments in position relative to said spider, at least one of said rings consisting of a plurality .of sections, and a comparatively narrow ring of insulatin material bridging the space between sai( commutator segmentsand said spider adjacent to one of said clamping rings.

4. In a commutator, the combination of a I supporting frame, a plurality of commutator segments, a ring for clampin said segments in position relative to said rame, said nng consisting of a'plurality of parts, and a ring of insulating material bridging the space between said frame and said segments at or near the .ends of the commutator segments adjacent to said clamping rin the axial dimension of said ring of ins ating material being less than that of such space.

5. In a commutator, the combination of a supporting frame, a plurality of commutator segments, a ring for clamping said segments in position relative to said frame, said ring consisting of a plurallty of parts, and a ring frame, a plurality of commutator segments,

means for clamping said segments in proper position relative to said frame, and two insulating rings spaced from-each other and spacing said frame and segments apart.

7. In a commutator, the combination of a sup' orting frame provided with a groove, a p urality of commutator segments, means for clamping said segments in proper position relative to said frame, and an insulating ring set in the groove in said frame and spacing it from said segments.

8. In a commutator, the combination of a supporting frame provided with a groove, a plurality of commutator segments, means for clamping said segments in proper posi" tion relative to said frame, andan insulating ring set in the groove in said frame and fun nishing a support for the ends of the comn I tator segments.

In testimony whereof I affix my signature, in the presence of two witnesses.

GEO. B. SoHpEY, FRED J. K msnr. 

